ESPA supplies Cat’s first solar plant in Adelaide

NAWMA project

More than 11,000 Cat PV solar modules are mounted on fixed-axis steel frames in an innovative first-of-its-kind renewable energy facility that combines solar and methane gas.

Energy Power Systems Australia (EPSA) was engaged by Joule Energy, a wholly-owned subsidiary of LMS Energy, in their partnership with Northern Adelaide Waste Management Authority (NAWMA).

EPSA provided a turnkey solution comprising engineering, design, construction and commissioning for the 1.15MW (ac) PV solar plant, which is utilising the unused portion of land next to the Uleybury Landfill site as a solar farm.

The waste creates methane gas formed by the breaking down of organics in the garbage and the Cat gas generator converts this methane into electricity that has been successfully exporting green energy into the South Australian grid since it was commissioned in late-October 2017.

The collective electricity generated from both the landfill gas and solar sources is expected to be more than 11,000MWh per annum of renewable energy.

When compared to a traditional coal-fired power station generating the same amount of electricity, the NAWMA renewable energy facility will save about 24 million litres of water each year and prevent the emission of around 63,500 tonnes of carbon.

The PV solar modules are arranged into 46 mini power blocks each feeding a dedicated 25kW (SMA) inverter, according to EPSA microgrid and hybrid segment manager Ron Hall.

“The strings are then combined into three separate arrays, with AC output from each collected to supply the EPSA-supplied HV transformer kiosk,” Mr Hall said.

“The kiosk transforms the voltage to 11,000V AC for supply to the grid via the client-operated power station.

“Control of the plant is achieved using the 4G wireless network to communicate between the power station and a Cat (SMA) Cluster Controller, which relays the information back and forth to each of the 46 inverters.

“The controller includes a web-connected online portal to provide the client with up-to-date information on the solar plant status including current plant output, daily yield and alarms.

“Since this solar plant is exporting to the grid, the grid voltage is affected with higher export values.

“To counter the ever-growing problem of grid voltage stability, the solar plant is able to dynamically change the output power factor to import or export 100 per cent of the plant’s output in reactive power in a trade-off for active power meaning that the plant can help stabilise the local grid voltage throughout the day.”

Landfills have very little utility once capped, due to issues of land settlement and landfill gas, making them ideal locations for solar development.

Solar generation systems on landfills, and adjacent buffer zones, provide an economically viable reuse for sites that may have significant clean-up costs and little potential for commercial or residential redevelopment.